Onto 5 or 6 long metal skewers, alternately thread pork chunks and plum quarters. Place skewers on grill over medium heat; cook 15 to 20 minutes, until pork just loses its pink color throughout, turning occasionally and brushing pork and plums with plum jelly during last 3 minutes of cooking.

To serve, arrange kabobs on large platter; sprinkle with chopped cilantro if you like.